1. Field of the Invention
The present invention relates to a solid-state audio recording unit for recording/playing back sounds by using a solid-state storing medium, such as a semiconductor memory, and, more particularly, to a solid-state audio recording unit having a recording confirming function.
2. Description of the Prior Art
An apparatus is known that digitally converts sound signals inputted from a microphone and then records the converted signals into a solid-state recording medium, such as a semiconductor memory (solid-state audio recording unit). This type of solid-state audio recording unit only digitally converts the input signals to be recorded in the memory and performs playback after completion of recording.
Therefore, a user can not perceive the situation that the recording actually failed unless the playback is performed after completion of the recording, even if the recording was not actually carried out due to an erroneous operation or the like.
It is to be noted that, in a recording apparatus using an analog tape, it is known that one can confirm whether the recording is actually performed on a real-time basis by using a playback head to reproduce signals recorded by a recording head in a so-called three-head mechanism, the playback head being provided immediately behind the recording head.
However, in a solid-state audio recording unit using the semiconductor memory, a recording confirming function is not known.
Incidentally, a dual-port memory may be used for simultaneously performing input and output in case of processing image data, but this type of memory is expensive and it is not suitable for holding the recorded audio data.
The present invention is aimed to solve the above-described problems, and an object thereof is to realize a solid-state audio recording unit being capable of confirming whether the normal recording is being carried out on a real-time basis.
The present invention provides a solid-state audio recording unit to deliver, while storing incoming audio data into a memory, audio data stored in the memory as an output on a real-time basis comprising two input buffers for alternately holding incoming audio data; a memory for storing audio data; two output buffers for holding audio data read from the memory; and a control means which, during a period when it forces one of the two input buffers to hold audio data according to a reference clock, and one of the two output buffers to deliver audio output outside according to the reference clock, writes audio data held by the other input buffer into the memory according to a second clock having a higher frequency than the foregoing reference clock; during a residual time of said period, reads audio data written into the memory according to a third clock having a higher frequency than the foregoing reference clock, and forces the other output buffer to hold them; and repeats the same operation alternately between the two input buffers and the two output buffers.
Although one of the input buffers which receives the incoming audio data from outside operates at a standard speed, the other input buffer which stores the audio data in the memory operates at a high speed. The successive data can be inputted/outputted by alternately operating these two input buffers.
Similarly, one output buffer which receives the audio data from the memory operates at a high speed, but the other output buffer for outputting the audio data to outside operates at a standard speed. In other words, when the data is stored in and read from the memory at a high speed, an operation such that input and output are performed at the same time deceptively is enabled even if the input/output port uses the single memory. As a result, the audio data stored in the memory can be outputted on a real-time basis.
It is to be noted that at least one of the second and third clocks has a frequency two or more times that of the reference clock.
The present invention further may comprise compressing means for compressing audio data to be written from the input buffer into the memory; and expanding means for expanding audio data to be read from the memory and held by the output buffer.